The present invention relates to a process for heat treating paste-forming polymers of vinyl chloride.
It is already known to after-treat polyvinyl chloride (PVC) powders intended for the preparation of pastes, by heating them to 30.degree.-40.degree. C. above the drier temperature (J. Delome, Rev. Gen. Caoutch. 40 (1963), No. 10, pages 1467 to 1474). Polyvinyl chloride powders which are subjected to this treatment, upon mixing with plasticisers, yield pastes having improved shelf life (compare Example 2 of the table herein). Since the drier temperatures are normally 55.degree. to 70.degree. C., the powders are warmed to 85.degree.-110.degree. C.
However, as can be seen from the comparative experiment of the table, Example 2 herein, such an after-treatment produces pastes having undesirable flow characteristics.